Poisonous, Greater (3.5e Equipment)
From D&D Wiki
Poisonous, Greater: A poisonous weapon deals initial and secondary temporary Constitution damage by poisoning opponents. The Fortitude saves to negate the damage and the damage, itself, increase the higher the caster level of the spell used to enhance the weapon. Bows, crossbows and slings so crafted bestow the poison upon their ammunition.
(1d10 Con; Fort DC 18 negate)
Strong necromancy;CL 12; Craft Magic Arms and Armor, poison; Market Price: +3 bonus